IT hiring managers and recruiters are bracing for a fight over the most skilled tech pros -- and they're watching carefully to make sure their own most valued employees aren't about to flee for greener tech pastures.

IT hiring managers and recruiters are bracing for a fight over the most skilled tech pros -- and they're watching carefully to make sure their own most valued employees aren't about to flee for greener tech pastures.

"The hiring game wasn't supposed to be this heated," writes Alice Hill, managing director at Dice.com, in a Web post. "Subpar job growth, modest economic expansion and wavering confidence should have given companies time to find talent."

Instead, a combination of factors -- including growing numbers of unfilled job openings and underpaid employees who want more lucrative jobs -- is causing a hiring rush that's expected to worsen this year.

Dice currently lists 75,000 available technology and engineering jobs, including full-time, part-time and contract positions.

In a study conducted last month by the careers site, 54% of hiring managers and recruiters said they expect tech talent poaching to get more aggressive this year. Another 33% of respondents expect the level of poaching to remain the same, while just 3% expect a let-up.

Industry watchers have been warning that unhappily employed workers are getting restless. As job openings increase, people who stayed in less-than-ideal jobs during the recession are jumping at a chance to find something new. Across all industries, CareerBuilder reports that 15% of full-time, employed workers are actively seeking a new job. Another 76% aren't actively looking, but said they would change jobs in 2011 for the right opportunity.

How can a company tell when a tech pro is thinking of jumping ship? The most obvious signs are a change in work habits and a noticeable lack of engagement with colleagues or projects, Hill says. But there are other tells, too. A large numbers of single-day absences can signal someone is in job-hunting mode, as can a switch to more formal attire. Another clue: suddenly getting up-to-date on expense accounts.

Meanwhile, companies are taking steps to retain their top IT talent. According to Dice, the most popular retention tactic is accommodating flexible work hours. That perk ranked first among the 2,697 hiring managers and recruiters polled last month. Other ways companies are trying to retain at-risk IT employees include (in order of popularity): offering work on new or emerging technologies; increasing salaries; providing better career opportunities; granting a promotion or new title; increasing bonus potential; and allowing telecommuting.

Of course, switching jobs doesn't guarantee happiness, and not every IT pro will find an open door if he or she decides to try to return to a previous employer. Hiring managers polled by Dice are split on the issue of rebound employees. While 33% said they would rehire an IT employee who has been previously poached, 11% said they wouldn't. More than half (56%) said it depends on the employee.